block: create the request_queue debugfs_dir on registration
We were only creating the request_queue debugfs_dir only
for make_request block drivers (multiqueue), but never for
request-based block drivers. We did this as we were only
creating non-blktrace additional debugfs files on that directory
for make_request drivers. However, since blktrace *always* creates
that directory anyway, we special-case the use of that directory
on blktrace. Other than this being an eye-sore, this exposes
request-based block drivers to the same debugfs fragile
race that used to exist with make_request block drivers
where if we start adding files onto that directory we can later
run a race with a double removal of dentries on the directory
if we don't deal with this carefully on blktrace.
Instead, just simplify things by always creating the request_queue
debugfs_dir on request_queue registration. Rename the mutex also to
reflect the fact that this is used outside of the blktrace context.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/block/blk-core.c b/block/blk-core.c
index a99b22f..a9769c1 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -51,9 +51,7 @@
#include "blk-pm.h"
#include "blk-rq-qos.h"
-#ifdef CONFIG_DEBUG_FS
struct dentry *blk_debugfs_root;
-#endif
EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap);
EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap);
@@ -555,9 +553,7 @@ struct request_queue *__blk_alloc_queue(int node_id)
kobject_init(&q->kobj, &blk_queue_ktype);
-#ifdef CONFIG_BLK_DEV_IO_TRACE
- mutex_init(&q->blk_trace_mutex);
-#endif
+ mutex_init(&q->debugfs_mutex);
mutex_init(&q->sysfs_lock);
mutex_init(&q->sysfs_dir_lock);
spin_lock_init(&q->queue_lock);
@@ -1931,9 +1927,7 @@ int __init blk_dev_init(void)
blk_requestq_cachep = kmem_cache_create("request_queue",
sizeof(struct request_queue), 0, SLAB_PANIC, NULL);
-#ifdef CONFIG_DEBUG_FS
blk_debugfs_root = debugfs_create_dir("block", NULL);
-#endif
return 0;
}
diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
index 15df3a3..a2800bc 100644
--- a/block/blk-mq-debugfs.c
+++ b/block/blk-mq-debugfs.c
@@ -824,9 +824,6 @@ void blk_mq_debugfs_register(struct request_queue *q)
struct blk_mq_hw_ctx *hctx;
int i;
- q->debugfs_dir = debugfs_create_dir(kobject_name(q->kobj.parent),
- blk_debugfs_root);
-
debugfs_create_files(q->debugfs_dir, q, blk_mq_debugfs_queue_attrs);
/*
@@ -857,9 +854,7 @@ void blk_mq_debugfs_register(struct request_queue *q)
void blk_mq_debugfs_unregister(struct request_queue *q)
{
- debugfs_remove_recursive(q->debugfs_dir);
q->sched_debugfs_dir = NULL;
- q->debugfs_dir = NULL;
}
static void blk_mq_debugfs_register_ctx(struct blk_mq_hw_ctx *hctx,
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 561624d..be67952 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -11,6 +11,7 @@
#include <linux/blktrace_api.h>
#include <linux/blk-mq.h>
#include <linux/blk-cgroup.h>
+#include <linux/debugfs.h>
#include "blk.h"
#include "blk-mq.h"
@@ -917,6 +918,9 @@ static void blk_release_queue(struct kobject *kobj)
blk_mq_release(q);
blk_trace_shutdown(q);
+ mutex_lock(&q->debugfs_mutex);
+ debugfs_remove_recursive(q->debugfs_dir);
+ mutex_unlock(&q->debugfs_mutex);
if (queue_is_mq(q))
blk_mq_debugfs_unregister(q);
@@ -989,6 +993,11 @@ int blk_register_queue(struct gendisk *disk)
goto unlock;
}
+ mutex_lock(&q->debugfs_mutex);
+ q->debugfs_dir = debugfs_create_dir(kobject_name(q->kobj.parent),
+ blk_debugfs_root);
+ mutex_unlock(&q->debugfs_mutex);
+
if (queue_is_mq(q)) {
__blk_mq_register_dev(dev, q);
blk_mq_debugfs_register(q);
diff --git a/block/blk.h b/block/blk.h
index 8ba4a5e..3a120a0 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -14,9 +14,7 @@
/* Max future timer expiry for timeouts */
#define BLK_MAX_TIMEOUT (5 * HZ)
-#ifdef CONFIG_DEBUG_FS
extern struct dentry *blk_debugfs_root;
-#endif
struct blk_flush_queue {
unsigned int flush_pending_idx:1;
